Eight male collegiate weightlifters (age: 21.2 +/- 0.9 years; height: 177.6 +/- 2.3 cm; and body mass: 85.1 +/- 3.3 kg) participated in this study to compare isometric to dynamic force-time dependent variables. Subjects performed the isometric and dynamic mid-thigh clean pulls at 30-120% of their one repetition maximum (1RM) power clean (118.4 +/- 5.5 kg) on a 61 x 121.9-cm AMTI forceplate. Variables such as peak force (PF) and peak rate of force development (PRFD) were calculated and were compared between isometric and dynamic conditions. The relationships between force-time dependent variables and vertical jump performances also were examined. The data indicate that the isometric PF had no significant correlations with the dynamic PF against light loads. On the one hand, there was a general trend toward stronger relationships between the isometric and dynamic PF as the external load increased for dynamic muscle actions. On the other hand, the isometric and dynamic PRFD had no significant correlations regardless of the external load used for dynamic testing. In addition, the isometric PF and dynamic PRFD were shown to be strongly correlated with vertical jump performances, whereas the isometric PRFD and dynamic PF had no significant correlations with vertical jump performances. In conclusion, it appears that the isometric and dynamic measures of force-time curve characteristics represent relatively specific qualities, especially when dynamic testing involves small external loads. Additionally, the results suggest that athletes who possess greater isometric maximum strength and dynamic explosive strength tend to be able to jump higher.

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Background There are no previous data describing nelfinavir and lamivudine pharmacokinetics in neonates treated with weight band dosing regimens. Design Pharmacokinetic study of nelfinavir and lamivudine pharmacokinetics in infants during the first 2 weeks of life treated with weight band dosing regimens. Methods Intensive 12 hour pharmacokinetic profiles were performed between either days 4–7 or days 10–14 of life in 26 Brazilian infants. Results Pharmacokinetic data were obtained from 26 infants who received median (range) per kg doses of 58.8 (48.4–79.0) mg/kg for nelfinavir and 2.0 (1.5 – 3.2) mg/kg for lamivudine. Median nelfinavir AUC0-12 was 25.5 (1.7 – 183.5) μg*hr/mL and median C12h was 1.09 (<0.04 – 14.44) μg/mL. AUC0-12 was less than 15 μg*hr/mL (the 10% percentile for adults) in 12 infants (46%). Median lamivudine AUC0-12 was 7.8 (2.7–15.6) μg*hr/mL and median C12h was 0.23 (<0.04 – 0.74) μg/mL. Conclusions Lamivudine pharmacokinetic parameters observed in this study were consistent with those seen in other studies of neonates. While median nelfinavir AUC and C12h in these neonates were above the exposure targets, interindividual variability in nelfinavir exposure was large and nelfinavir exposure failed to meet the exposure targets in 46% of infants.

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